Solar power generators are becoming popular. They convert solar power to electric power with solar cells and, for example, either supply the electric power to electric loads or export the electric power to a power grid. By DC-coupling the solar cells to a storage battery, the solar cells can charge the storage battery with high efficiency. This configuration eliminates the need for a DC/DC power converter for voltage conversion between the solar cells and the storage battery, and for this reason, provides an inexpensive power conditioner (see Patent Literature 1).
Patent Literature 2 discloses a system that includes a DC-coupled storage battery and solar cells so that the system can operate even during a power outage. Patent Literature 2 further discloses some operation examples of on/off switches for the solar cells and storage battery during a power outage.